Method of shaping filaments.



R. W. SUMAN. METHOD 'OF SHAPING FILAMENTS.

APPLICATION FILED MAY 31, 1911.

Patented J an. 2, 1912.

' Fig. 3

y l ll Inventor Ruppert W. Suman,

To all whom it may concern:

UNITED STATES PATENT OFFICE.

RUPPERT W. SUMAN, 0F NEWARK, NEW JERSEY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD OF SHAPING FILAMENTS.

Be it known that I, RUPPERT W. SUMAN, a citizen of the United States, residing at Newark, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Methods for Shaping Filaments, of which the following is a specification.

My invention relates to the shaping or forming of wires, filaments, and the like, and it comprises a method applicable for this purpose.

According to my invention, fully shaped filaments ready to be placed on their supporting means can be produced, and the shaping operations are simple, easy, and expeditious.

The invention allows a plurality of filaments of exactly the same configuration and dimensions to be obtained one at a time, in a lot, or in successive lots; makes it possible to produce in this manner forms comprising one or more recurring shapes with the certainty that such shapes shall recur with perfeet regularity and exact uniformity; and ofi'e'rs various other advantages. It may be used with especial advantage when any part of the supporting means 'for the filament is too weak to stand the strain that would be imposed thereon if the filament were given its form as an incident of the operation of placing it on the supporting means,-as when the filament is engaged by members which are made light so as to be resilient. It is applicable in connection with the manufacture of apparatus having filaments of Y tungsten, tantalum, and any other refractory metals and materials. It may be utilized when the filament material is in its final condition or at some intermediate stage of manufacture, according to convenience, the material of the filament, and the process of manufacture. For example, when filaments of refractory metalas tungstenare made by incorporation together of the refractory metal and auxiliary metallic material and working of the product into the desired shape by squirting, rolling, drawing, or in other ways, my invention may be applied prior to the elimination of the auxihary metal from the wire.

I have hereinafter described a procedure "and an apparatus in accordance with my invention t at may be used in connection with the manufacture of incandescent lamps hav- Specification of Letters Iatent.

Application filed May 31, 1911.

Patented Jan. ,2, 1912. Serial No. 630,432.

ing filaments of drawn tungsten (which may be produced as described in British Patent #223,499 of 1909), the filament being shown as arranged in a sinuous or zig-zag form after the manner of tantalum lamps of well known commercial type; but it is to be understood that the invention can be carried out and applied in various other ways, and that it may be used (as above intimated) for the production of shaped filaments of other and more complex forms. According to the procedure in question, the wire is wound and formed on a shaping device, and the resulting coil is removed from the device and its convolutions separated. When the wire to be dealt with is quite resilient, like drawn tungsten Wire, it may be found desirable to subject its bends to some special treatment to set them before removing the wire from the shaping device; but when it is soft and yielding this may not be necessary.

In the accompanying drawings, Figure 1 is a perspective view of a shaping deviceor form constructed in accordance with my invention, and shows a Wire or filament wound thereon; Fig. 2 is a view of a shaped filament; Fig. 3 shows a lamp mount with the filament in place thereon.

driven into holes in the base B,'as shown, or r they may be secured in any suitable manner. If desired, they may be made adjustable. The dimensions of the device shown in Fig. 1 are larger than would usually be employed; when it is used for shaping the filaments of multiple. type tungsten lamps of moderate candle-power, the base may consist of a block of molybdenum about -}x1}"x 2%", and the tungsten pins may be about g in diameter and may be set about 115" between centers. Ffir reasons which will hereinafter appear, it is desirable that when used with drawn tungsten wire, for ex-' ample, the device should be made of some material (such as those mentioned) infu'sible at about 1400 C. and not liable to alloy with tungsten below that temperature.

In the production of simple sinuous or zig-zag filaments with this shape), the wire 'w is wound back and forth between; the pins P and 1? in the following manner: Starting from the end a, it is first carried around the pin P in a clockwise direction, then around the pin P in a counter-clockwise direction, then again around the pin P in a clockwise direction, etc., so that when viewed from above the elongated coil or wire presents the appearance of a crossed belt or a figure eight. For greater clearness of illustration, the ends a and 0 are shown as simply extending past the pin P a short distance; but when the wire is resilient, it may in practice be found convenient to carry the end a around the pin to the extent of one or more turns or otherwise secure it "before the winding back and forth between the pins is begun, and to finally carry the end 0 around the pin, etc., for a similar purpose. Of course the ends a and 0 might be twisted together after the winding is completed; or the end a might initially be secured in a hole or a slot in the base B and the end 0' might finally be secured in a slot in the pin P etc.

In order to set the bends of drawn tungsten wire, for example, and thus insure that after removal it shall sufficiently retain the shape which it had on the shaping device, the wire may be heated to a suitable temperature in an atmosphere which will not affect either the wire or the shaper.-

Thus the shaper with the wire upon it may be baked oi fired in an electrically heated furnace consisting of a platinum wound porcelain tube inclosed in silica and firebrick hydrogen or the mixture of hydrogen and lifitrogen known as forming gas being ssed through the furnace. For tungsten wire a temperature of about 1000 Centigrade to 1100 or 1250more or less, will be found satisfactory. The wire need not be iaeated any length of time. Any furnace in which the proper conditions can be produced may be used.

When cool the wire may be removed from the shaping device by pulling the pins from their holes in the base B, or even by simply slipping it ofi the pins without disturbing them, if the wire is not too tight on them. Then the convolutions of wire and the straight lengths or sections comprised in them are separated, transversely of the coil as shown in Fig. 2. The shaped filament may now be placed on the supporting frame or spider F, its bends '59,, etc. and p etc.

engaging with the light,resilient holders h,

and 1ts ends may be secured to the current leads Z, Z in any approved manner. It will be understood, of course, that the number of bends'given the wire on the shaping dey vice will correspond to the numberof arms in the supporting fi-ame'. on which it is to be carried: lgs. 1 and 20f the drawing show the wire as having two bends in excess of exactly alike.

20,, 12 etc. and 70 p 70, etc. on the same plns, respectively, and the extension of all the straight portions of the filament between these pins result in each filament being regular and uniform throughout and in all the filaments made on the same shaper being This regularity and uniformity of the filaments enhances the appearance of the mount, reduces short cir cuits due to vibration of Very slack filament sections and breakage caused by shrinkage of excessively taut sections, and generally improves the mechanical qualities of the finished lamp. It also allows the manipula' tion and bending of the engaging parts of the filament supporting system or frame and the other work involved in the placing of the filament thereon to be reduced to the minimum,-in part through standardization of the supporting system to the point of greatest regularity and uniformity consistent with economy in manufacture,-reduces breakage of lamps during manufacture, and decreases the cost of production and facilitates it in Various ways.

It will readily be apparent that shaping devices of various forms and constructions can be used, and that by employing a suitable number and arrangement of pins or other elements of proper size and shape a or less nearly analogous to the successive bends of the form shown.

What I claim as new and desire to secure by Letters Patent of the United States is 1. The method of shaping filaments which consists in Winding and forming the wire or filamentary thread in a coil comprising a suitable number of convolutions and separating the convolutions in a direction perpendicular. to the axis of the coil so as to cause the convolutions to lie side by side.

2. The method of producing a shaped filament comprising a plurality of portions of the same recurring shape which vconsists in winding and forming the wire in a coil comprising a 'lurality of similar convolutions, the wlre eing carried through successive bends in opposite directions and separating I the convolutions of wire in a direction trans verse thereto.

3. The method of producing a zig-zag or sinuous filament which consists in winding and forming the Wire from which the filament is to be produced in a coil comprising a plurality of superposed convolutions resembling a figure eight and separating the convolutions in a direction transverse thereto.

4. The method of producing a shaped fila' ment comprising a plurality of portions of the same recurring shape which consists in winding and forming the wire from which the filament is to be produced in a plurality of convolutions on a shaping device so that the homologous recurring portions shall be shaped upon the same part of the device and removing the wire therefrom and separating its convolutions in a direction substantially in the plane in which a convolution is wound, so as to cause the' convolutions to lie side by side.

5. The method of producing a sinuous zigzag filament of tungsten wire which consists in winding and forming the wire in a plurality of convolutions on a shaping device so that analogous recurring portions shall be shaped on the same part of the device, heating the wire while on the device to a sufiicient temperature to set its bends, and then removing the wire from the device and separating the convolutions in such manner as to cause them to lie side by side.

6. The method of producing a zigza' or sinuous filament which consists in winding and forming the wire from which the filament is to be produced in a coil comprising a plurality of superposed convolutions, the wire being carried through successive bends in opposite directions, heatin the wire to a sufficient temperature to set its bends, and then separating the convolutions in a direction transverse thereto.

In witness whereof, I have hereunto set my hand this 20th day of May 1911.

RUPPERT W. SUMAN. Witnessesi S. N. WHITEHEAD, J. H.'ELKINS. 

